07-30-2012, 07:25 AM #1
- Join Date
- Jul 2012
1998 GTXL Cavitation. Please hlep
Boy could I use some help from the resident Jetpumpexperts. This is going to be a bit longbut I want to give you all the information I have. Bought a 98 GTXL with a blown motor and 300hours on it. So I rebuilt the motor andalso rebuilt the jetpump since it had so many hours and I did not know themaintenance history on the ski.
On the pump I replaced all the bearings and seals a longwith the shaft. One of the bearings hadspun and the diameter of the shaft was just out of tolerance. Replaced the wear ring as well. The impeller was a little beat up but wecleaned it up a bit and used it.
When I first put the ski in the water it was working prettygood with just a little cavitations. The amount of cavitations seems to get worst and it got to the pointwhere I had to get to 20 MPH before the cavitations would stop and the skiwould take off.
I replaced the intake crate with a Solas unit and pulled thepump and installed a Solas Concord impeller. Took it out on the lake yesterday and it seems even worst then beforethe intake and impeller replacement.
This year and model jetski was built with two differentdrive configurations depending on when it was built. At one point I was reading on the forumsabout the carbon seal and using the bellows to apply pre-load the carbonseal. I figured this was my problem andpurchased some heavy duty tie wraps to try that little trick to stiffen up thebellows. When I got home I realized thatmy drive setup was different and that I did not have a bellows. My ski has a thick rubber hose about 4 incheslong with clamps on both ends. So noCarbon seal but a couple of regular seals on the driveshaft inside theski. These seals are the only thing Ican think of at this point to blame my problem on.
One last note, I did not use an alignment tool when Iinstalled the engine back into the ski after the rebuild. Summer is running out and I would like to getthis thing set before the snow flies. Any suggests would so greatly be appreciated.
PS I have no water leaking into the ski
07-30-2012, 07:49 AM #2
- Join Date
- Oct 2005
07-30-2012, 08:04 AM #3
I've been working on Seadoo for a long time and never had the carbon seal or bellows cause any kind of cavitation problem, although I could see a bellows or seal leaking air into the pump if the water pulled a vacuum on it and it leaked. However, loose or damaged bellows and seals have only led to water leaking into the hull for me.
Its pretty easy to damage a wear ring, make sure it still looks good, I'm sure you did. There is a thick washer that goes umder the impeller and bearing, if that is missing you'll have big time cavitation as that gives too much space between the impeller and wear ring. I don't remember the proper clearnace but its pretty low, like 2mm, bewteen impeller and wear ring at the leading edge.
Hmmm...what else. Usually engine alignment just causes vibration and bearing damage, but I can see it causing carbon seal and bellow issues too if it was pushing on them to one side. Might pull the shaft out and just make sure its not slightly bent.
07-30-2012, 08:05 AM #4
Oh, make sure you have the rubber nose cone installed and its not all bunched up or ripped.
07-30-2012, 08:34 AM #5
- Join Date
- Oct 2005
this gtx is a ski correct? and this is the boat forums? The OP reports he has the sealed bearing carrier and no carbon seal...
also if the engine is way out the carbon rings don`t last long and will cause cav. On my boat, both carbon rings were wasted from every possible cause...
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